Isolation and ex-vivo Activation of Adipose-derived Cells

In recent years stem cell research has become increasingly important for regenerativemedicine and tissue engineering. The isolation of stem cells from adipose tissue evades ethicalconcerns with which embryonic stem cells and induces pluripotent stem cells (iPS) are afflicted,because of its declaration as clinical waste material. Tumescent liposuction is a minimallyinvasive procedure providing high amounts of adipose tissue rich in therapeutically relevantcells within a short time. The isolated stromal vascular fraction (SVF) and the adipose derivedstromal/stem cells (ASC) contained therein show a high regenerative potential and have beensuccessfully used in many clinical studies. Maintaining SVF cells in their natural environmentand therefore providing the maximum possible regenerative potential of adipose tissue-derivedcells is a prerequisite for successful autologous clinical application. With an improved gentleand fast isolation process by minor manipulation it is possible to obtain a therapeuticallyrelevant cell population. A physical stimulus already used in clinics is the extracorporealshockwave therapy (ESWT), shockwaves are characterized by their high rise in pressurewithin a very short time followed by cavitation wave with a negative amplitude. By applyinglow-energy ESWT on freshly obtained human liposuction material and isolated SVF cells (invitro) we aimed to equalize and enhance stem cell properties and their functionality. We wereable to show an increased adenosine tri-phosphate (ATP) concentration after applying ESWTon adipose tissue as well as a significantly increased expression of single mesenchymal andvascular surface markers in comparison with the untreated group. Additionally, the proteinsecretion of insulin-like growth factor 1 (IGF-1) and placental growth factor (PLGF) wassignificantly enhanced. Further it was investigated if there is the same beneficial effect whenapplying ESWT on the adipose tissue harvest site before liposuction to improve cell propertiesin situ. We showed a significantly enhanced viability, ATP concentration and populationdoublings after 3 weeks in culture for cells isolated from ESW treated adipose tissue harvestsite. Further the expression of mesenchymal and endothelial/pericytic markers was elevatedcollaborating with the increased angiogenic differentiation potential as well as the increasedsecretion of certain angiogenic proteins after ESWT in situ. Besides ESWT the effect of anotherphysical stimulus on SVF/ASC cells was tested - Low level laser therapy (LLLT) has alreadyshown beneficial effects. Therefore, we investigated effects of pulsed blue (475nm), green(516nm) and red (635nm) light from light-emitting diodes (LEDs) applied on freshly isolatedSVF cells. Cells had a stronger capacity to vascular tube formation after exposure to greenand red light concomitant with an increased concentration of vascular endothelial growth factor(VEGF) in the secretome. In a side project during the PhD program the hormone-relatedwomens disease lipedema was investigated. The SVF cell properties of healthy and lipedemapatients were investigated and a significant enhancement in cell yield as well as a reduction inadipogenic differentiation capacity of lipedema SVF cells was revealed. Within this workdifferent physical forces applied on adipose tissue and adipose tissue-derived cells werepresented as well as an improved isolation method and characteristics of degenerated adiposetissue. This are promising applications for the clinical use in the field of regenerative medicineand tissue regeneration.

Accepted: 2020-06-27T19:21:04Z